Notes On Using Hdlm; Notes Common To Oss - Hitachi XP P9500 User Manual

4. HDLM Operation

4.1 Notes on Using HDLM

Note the following when using HDLM.

4.1.1 Notes Common to OSs

The following notes are common to OSs:
Do not activate the same volume group concurrently from multiple servers.
When a path error exists, the period of time required to return a response to the
application that made an I/O request to HDLM depends on the timeout values
specified for the fibre channel switch and HBA.
Therefore, if an error occurs in all the paths for a single LU, this response time
will be the total period of time required for the corresponding fibre channel
switches and HBAs to detect a timeout for the I/O requested for each path.
For details on the timeout values for fibre channel switches and HBAs, see the
appropriate manual for the device. Figure 4-1: Overview of the Period Required
to Respond to an Application's I/O Request gives an overview of the period
required to return a response: from the time an application requests an I/O, to the
time the application receives the response.
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